Strictly PC gaming, right? Consider an Auzentech X-Fi Prelude or X-Fi Forte, unless you really need to keep the costs down, in which case the Asus Xonar DG becomes a very tempting option. CMSS-3D Headphone or Dolby Headphone will give you the surround sound you want.

Does it have to be a headset? You'd have a lot more options with a clip-on or desk mic and conventional stereo headphones to use. But if it has to be...I saw a Sennheiser PC360 on eBay for just under $200 when most go for around $250.

I like the way you can customize it, and really f''k the prize I just want some of the best out there so I don't need to upgrade and I don't feel sad then I see Razer Tiamat 7.1 come out cause I know I got something better :P

I will look that soundcard up mate, but I saw that it had 192 Kbp/S isn't that low? I see songs with 320Kbp/S

And Do I need an MixAmp for DT 990? Or Rather would it be better? If that's the case ofc I buy that one. Just dunno which one :P

Sampling rate denotes how many times a sound is measured per second. It's said that 192 KHz actually yields worse results than 96 KHz due to artifacts in the process, but I'm already hard-pressed to hear a difference between 48 KHz and 96 KHz.

While I'm at it, I might as well also mention bit depth (often mentioned before sampling rate), which denotes the dynamic range of those samples. 24-bit depth basically means there's a wider volume range than 16-bit depth.

Bit rate has to do with digital file formats and how much information they have. Most codecs like MP3, AAC, OGG Vorbis, and so forth throw out a lot of the information in order to keep file size small, which naturally reduces the bit rate; hence, they're called lossy. Some codecs like FLAC compress in a manner that doesn't discard any of the original audio information, which is why we call them lossless. (WAV is raw and uncompressed.) Naturally, files that are larger in size are going to have higher bit rates, though whether you'll perceive any difference in quality above a certain point (depending on set bit rate and codec; a common comparison is MP3 320 Kbps vs. FLAC) may vary.

The Astro Mixamp is mostly used by console gamers because consoles output surround sound over S/PDIF (digital Toslink/optical). If you're a PC gamer who has no need for cross-compatibility with consoles, you can just use an internal sound card and reap the same benefit at lower cost or with higher quality.

If you wanted the very best...well, I don't think anyone's going to spend Stax SR-009 + Blue Hawaii SE money with gaming in mind (we're talking around US$10,000 here), but any Head-Fi-worthy headphone in the $200-300 range should outdo gaming headsets in general. (Keep in mind that that figure does not include sound cards or amplifiers.)

Headsets from companies like razer tend to have mediocre to terrible build quality and price:performance ratios, so i could never really recommend them, and the DT990s are very nice headphones, i say go with those and a cheap desk mic or one you could just stick to the side of the phones

Don't worry about the Razer headsets. Just get the DT 990 or whatever else has the sound signature you like while not compromising on functionality with CMSS-3D Headphone or Dolby Headphone. (As a general rule, it's said that headphones with wider soundstages do better, though some actually prefer closed Ultrasones instead of typical open headphones.)

I Just read that DT 990 would make .Mp3 files sounds awful is that true? Cause if that's the case. I really dunno If I should buy them since I have alot of .Mp3 files. (Using Itunes cause of IPhone i don't like Itunes)

Atm I design it and i'm really wanna buy it, but if .Mp3 files sounds bad I would not even mind it :P

Some might say that, but it seems to me that even lossily-compressed MP3s sound fine in general on higher-end headphones.

It's just that if there are any flaws in the source recording, you're far more likely to notice, and if you've heard a lossless version of the same song, you might notice details that were lost in compression.

(If anything, I'd expect my Stax Lambda setup to be mercilessly revealing, being electrostatic and all, but just about anything I play sounds great through these if there's not something horribly wrong with the source to begin with. It could also be just as much that I don't have tuned audiophile ears yet.)

In terms of impedance for Beyerdynamic offerings in general...hard to say, but they're all said to be pretty insensitive (even the lower-impedance ones) and benefit from an amp. Getting the usual 250-ohm version and a FiiO E9 to drive it should do the trick.